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<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        #box{
            width: 1000px;margin: 0 auto;}
        li{float:left;list-style: none;margin: 5px;background: #ccc;}
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    <ul>
        <li>111</li>
        <li>222</li>
        <li>333</li>
        <li>444</li>
        <li>555</li>
        <li>666</li>
    </ul>
</div>
</body>
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